Demountable air pumps for sewing machines



Oct. 25, 1955 R, HAPPE 2,721,692

DEMOUNTABLE AIR PUMPS FOR SEWING MACHINES Filed DSC. 24, 1949 4 Sheets-Sheet l Oct. 25, 1955 R. HAPPE DEMOUNTABLE AIR PUMPS FOR SEWING MACHINES Filed DGO. 24, 1949 4 Sheets-Sheet 2 Oct. 25, 1955 R. HAPPE DEMOUNTABLE AIR PUMPS FOR SEWING MACHINES 4 Sheets-Sheet 5 Filed Dec.

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DEMOUNTABLE AIR PUMPS FOR SEWING MCHNES Filed Deo. 24. 1949 4 Sheets-Sheet 4 DEMOUNTABLE AIR PUMPS FOR SEWING MACHINES Reynold Happe, Pittstown, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of .N ew Jersey Application December 24, 1949, Serial No. 134,958

2 Claims. (Cl. 230-15) This invention relates to air pumps for supplying air under pressure to sewing machines for cooling needles and other purposes. More especially, it relates to means for readily mounting an air-pump for direct drive from the usual sewing machine power-transmitter with provision for accommodating axial movement of the transmitter-shaft incident to the clutch operation thereof.

It has been known, heretofore, to provide air blowers, driven by the usual power-transmitter, for supplying air to sewing machines while said machines are in operation. It has been customary, in these cases, to rigidly secure the housing of the blower to the transmitter frame, which construction requires critical alignment of the shafts and clearance within the blower housing for endwise movement of the shaft. This is especially diicult where the air blower has to be attached to existing power-transmitters in the iield.

These diiiiculties have been largely eliminated in the present invention by employing a novel construction for mounting the air-pump or blower. f

It is, therefore, a primary object of this invention to provide a mounting structure for an air-blower which may be attached to a sewing machine power-transmitter with a minimum of effort and Without any critical its.

It is a further object of this invention to provide an air-pump which may be attached to the shaft of a sewing machine power-transmitter of the type having an endwise movable shaft, in such a manner that the pump moves bodily with the movement of said shaft.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of preferred embodiments of the invention, from which 'the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings:

Fig. 1 is a side elevation, partly insection taken through a sewing machine power-transmitter and an airpump embodying the invention.

Fig. 2 is an end elevation of the apparatus of Fig. l.

Fig. 3 is an enlarged section taken through the air pump on lines 3 3 of Fig. 2.

Fig. 4 is an end elevation of a modification of the apparatus of Fig. 1.

Fig. 5 is a longitudinal section partly in elevation, the section being taken on lines 5 5 of Fig. 4.

Fig. 6 is a vertical section partly in elevation, the section being taken on lines 6 6 of Fig. 5.

Fig. 7 is an elevation partly in section, showing an alternate method of securing the plate 42 of Fig. 5.

Fig. 8 is an elevational view taken on the lines 8 8 of Fig. 7, with the guard-bracket partly broken away.

Referring to Fig. 1, a power-transmitter 1 is shown supported from a bracket 2 secured to the under side of a table 3 by means of bolts 4 4. This power-transmitter is shown and described in the U. S. Patent No.

' United States Patent O 2,721,692 Patented Oct. 25, 1955 2 2,597,685, of Edgar P. Turner, iiled September 13, 1946, to which reference may be had for a more complete disclosure thereof.

Inasmuch as the specific transmitter-structure forms no part of this invention, it is suiicient here to note that a power take-oft' shaft 5 is shifted axially by manual operation of a rod 6 to move a driven element 7 selectively into engagement with a driving friction disk 8 or with a friction brake-ring 9 depending on Whether driving or braking of the shaft 5 is desired, in accordance with usual transmitter practice.

A pulley 10 secured to the shaft 5 carries a belt 11 for transmitting power to a sewing machine (not shown) mounted upon the table 3.

An air-pump of the conventional rotary vane type has a housing 12 formed with a chamber 13, within which is positioned a rotor 14 and vanes 15. The rotor is carried by a shaft 16 journaled at one end in a 'Dallbearing 17 secured in a boss of the housing 12, and at the other end in a ball-bearing 18 secured in a coverplate 19 for the chamber 13, the cover-plate being secured to the housing 12 by means of screws 20. A fan 21 secured to the shaft 16 exteriorly of the housing 12 operates within an annular recess 22 formed in the housing to provide cooling air for said housing. This cooling effect is increased by the use of radial fins 22 formed on the exterior of the housing and terminating at their outer and rearward ends in a ring 35.

Formed on the exterior of the cover-plate 19 are spaced lugs 23 which are provided with at shoulders 23 to afford a seat to receive a restraining member which holds the pump housing against rotation but which offers a minimum restraint against axial move.

ment thereof.

The restraining member is formed from a at strip of spring metal and is bent to form two mutually perpendicular limbs 24 and 25 connected by a curved portion 26 of large radius relative to the strip thickness. One limb 24 is secured atwise against the under side of the table 3 by means of screws 27. The other limb 25 has a portion thereof covered with a sleeve 28 lof stretched rubber or other suitable resilient material, which portion is disposed in engagement with the seat afforded by the lugs 23, so that the sleeve forms a resilient cushion between the limb 25 and the lugs 23.

The outer end 5 of the shaft 5 is threaded and ordinarily receives a nut (not shown) to secure the pulley 10 thereto. According to the present construction, the pump shaft is formed with a hub portion 29 which is internally threaded to receive the end of shaft 5. Thus the hub 29, when screwed to the shaft 5, takes the place of the usual nut in securing the pulley to the shaft. A set screw 39 prevents accidental unscrewing of the parts thus secured.

It will be seen that the iiat surfaces of the limb 2S lie in planes perpendicular to the axis of the pump shaft and this construction provides a maximum restraint against rotation of the pump housing as the shaft rotates. Further, the curved portion 26 provides a minimum of restraint against axial movement of the pump imparted thereto by endwise movement of the transmitter-shaft 5 for clutch operation. The spring force is, however, sufficient to maintain the limb 25 in engagement with the lugs 23.

As seen best in Fig. 3, the cover-plate 19 is provided with an air inlet opening 31 and an air delivery opening 32. A exible tube 33 connects with the opening 32 to conduct the air to the vicinity of the needle or other point of use. It will be seen that the openings 31 and 32 interchange their functions when rotation of the pump shaft is reversed. The tube 33 is equipped with a threaded coupling 34 which may be coupled to either opening to facilitate adaptation to transmitters of either rotation.

In effect, this construction provides support for the pump housing 12 on the pump shaft 16 which, in turn, is supported on the transmitter shaft 5. The only alignment necessary in mounting the pump is that incident to the engagement of the restraining member with the lugs 23 and this is in no sense critical. In fact, the pump may be attached to the transmitter almost as easily as the nut, which place it takes in securing the pulley 10 on the shaft 5.

Fig. 4 shows another embodiment of this invention and is, in fact, the preferred embodiment. Substantially the same air-pump as shown in Fig. 1 is employed but the means for restraining the rotation of the pump housing has been modified. A cover plate 19' is provided with an air inlet opening 31 and an air delivery opening 32. The housing ring 35 is formed with a sent 36 extending over the lower half of its periphery for receiving a bracket 37. Lugs 38 formed on the ring 35 are apertured to receive screws 39 which are tapped into the bracket 37, as shown, to secure said bracket to the pump housing. The bracket 37 is cupped around the pulley 10 and forms a guard therefor. Paired radial lingers 40 and 41 formed on the periphery of the bracket 37 provide two spaced fork elements. A plate 42, secured to a stationary housing 43 of the power-transmitter by means of screws 44, carries a pin 45 covered with a sleeve 46 made of rubber or other suitable resilient material, which covered pin is presented between the lingers 40 and 41 of one of the fork elements, thus to restrain the pump housing against rotation.

It will be seen by reference to Fig. 6 that the plate 42 is formed with a depending offset portion 47 to which the pin 45 is removably secured by means of a nut 48 and lock washer 49. This oliset construction is to avoid interference with the clutch-actuating mechanism shown generally as 50. It is also clear that, by reversing the pin 45 on the plate 42 and reversing the plate 42 on the housing 43, an alternative arrangement is readily obtained in which the pin lies to the left of the clutchactuating mechanism as viewed in Fig. 6, in which case the pin 45 is embraced by the left fork element of Fig. 4. These alternative arrangements permit iiexibility in meeting individual clearance problems in the field.

As seen in Fig. 4, the covered pin 45 tits loosely within the fork element so that there will be a minimum of restraint against endwise movement of the pump housing incident to the axial movement of the power-transmitter shaft 5 during clutch operation. construction makes it unnecessary to secure any restraining member to the table, as was done in the case of the apparatus of Fig. 1. The only fastening elements required in adapting this air-pump to the power-transmitter are the set-screw 30 and the plate fastening screws 44-44, thus making it a simple installation in the field.

This modified t Power-transmitters of the type shown and described inthe U. S. Patent No. 2,004,055 of W. J. Peets et al. are provided with a brake vsupporting rod 51 threaded into a stationary frame member 52, as shown in Figs. 7 and 8. This affords a ready mount for the plate 42 as shown, the plate having an apertured portion 53 for receiving the rod 51 and the regular lock nut 54 being employed to secure the plate 42 firmly against the face of the frame member 52. This structure employs but two fastening elements, viz. the set-screw 30 and the lock nut 54, to attach the air-pump to power-transmitters in the field, thus requiring a minimum of tools and labor for its installation.

Having thus set forth the nature of the invention, what I claim herein is:

1. In combination, a power-transmitter having a stationary housing and an endwise shiftable power take-off shaft, an air pump including a rotor-shaft connected rigidly to said power take-off shaft to perform rotary and axial movements therewith, a chambered housing mounted upon said rotor-shaft and confined thereupon for bodily movement with the axial movements of the rotor-shaft, and rotation restraining means secured to said power-transmitter and in engagement with said chambered housing.

2. In combination, a power-transmitter having a stationary housing and a power take-off shaft which is movable endwise, a stationary support for said power-transmitter, an air pump, a housing for said pump, a rotor in said pump housing, a shaft for said rotor and journaled in said pump-housing, said pump housing, rotor and rotor-shaft being movable as a unit in an endwise direction, spaced lugs formed on said pump housing, a restraining arm formed of at strip material secured at one end to said stationary support and positioned in engagement with the lugs with the iiat surfaces of said arrn disposed in planes lsubstantially perpendicular to the axis of the pump shaft to provide maximum restraint against rotation of said pump housing, and screw means for rigidly securing said power take-off shaft to said pump shaft for driving same.

References Cited in the file of this patent UNITED STATES PATENTS 1,263,166 Walker Apr. 16, 1918 1,294,564 Strickland Feb. 18, 1919 1,663,253 Hillborn Mar. 20, 1928 2,265,971 Paul et al. Dec. 9, 1941 2,418,429 Sauer Apr. 1, 1947 2,423,996 Rubel July 15, 1947 2,424,102 Vesconte July l5, 1947 2,518,725 Sauer Aug. 15, 1950 

